title: Psychrotolerant antifungal Streptomyces isolated from Tawang, India and the shift in chitinase gene family.
abstract: A total of 210 Streptomyces were isolated from the soil samples of Tawang, India where temperature varied from 5 °C during daytime to -2 °C during the night. Based on antifungal activity, a total of 33 strains, putatively Streptomyces spp., were selected. Optimal growth temperature for the 33 strains was 16 °C, with growth occurring down to 6 °C but not above 30 °C. Phylogenetic analysis based on 16S rDNA sequences revealed the taxonomic affiliation of the 33 strains as species of Streptomyces. To examine the relatedness of the chitinase genes from six strong antifungal Streptomyces strains, a phylogenetic tree was constructed using the catalytic domain nucleotide sequences and resulted in seven distinct monophyletic groups. A quantitative PCR study for chitinase expressing ability revealed that of the six antifungal strains tested, the strain Streptomyces roseochromogenus TSR12 was the most active producer of family 18 chitinase genes. Streptomyces strains with enhanced inhibitory potential usually encode a family 19 chitinase gene; however, our present study did not show expression of this family in the six strains tested.
authors.affiliation: Biotechnology Division, CSIR-North East Institute of Science and Technology (CSIR-NEIST), Jorhat, 785 006, Assam, India.
authors.forename: Rajal
authors.initials: R
authors.lastname: Debnath
authors.forename: Ratul
authors.initials: R
authors.lastname: Saikia
authors.forename: Rupak K
authors.initials: RK
authors.lastname: Sarma
authors.forename: Archana
authors.initials: A
authors.lastname: Yadav
authors.forename: Tarun C
authors.initials: TC
authors.lastname: Bora
authors.forename: Pratap J
authors.initials: PJ
authors.lastname: Handique
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020134:Catalytic Domain; D002688:Chitinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003080:Cold Temperature; D005798:Genes, Bacterial; D007194:India; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013302:Streptomyces / Q000145:classification / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; D002688:Chitinases